Heretofore, run length encoded transition data to be imaged had to be in the sequential order of display. Transition data in non-sequential formats (such as edge by edge or face by face) required as intermediate storage from which the transition data could be sequentially retrieved. The transition data format included a display data portion followed by a run length code specifying the number of non-transition pixels until the next transition code. As each transition code was decoded and clocked through the image processor for display, the associated run length was entered into a register and decremented by the clock pulse until expiration (run length=0). At expiration, the next transition code and run length in the input sequence was advanced for display.